I think the best way way to conceive of technological progress is in terms of node density, where each node is a person. That is why I define the following terms the way I do:

Web 1.0 lets individuals create and express ideas

Web 2.0 lets groups create and express ideas

Web 3.0 lets societies create and express ideas

Notice that what causes each qualitative shift are new inventions/innovations that allow for increasing densification of nodes. Notice also that it's a rather beautiful idea in the mathematical sense, because web 3.0 is different from web 2.0 in exactly the same way that web 2.0 is different than web 1.0.

That's why I hate this whole "web 3.0 is the semantic web" meme, because it's completely arbitrary and lacking in any parallelism.